Why do we sleep at night and remain active during the day?

Our physiological routines and rhythms are governed and controlled by an internal timekeeper that maintains a 24-hour circadian cycle. This circadian cycle is why some people are “night owls” who are more active late in the day and go to sleep in the early hours while others are “morning larks” who have the opposite pattern of activity. Read more to understand what sleep disorders can occur due to disruptions or misalignment of this internal circadian clock.